In constructing or rehabbing buildings, homes, and the like, studs are secured vertically to define a frame for walls of the building. Electrical conductors, such as wiring, are secured to the studs to provide electricity and other utilities throughout the building. Plasterboard (drywall) is thereafter secured to the studs with screws, nails or other fasteners to form the walls of the building. Typically, nail or screw guns are used to rapidly and forcefully drive fasteners into the studs. Because the studs are behind the drywall, and because the fasteners are installed rapidly with a gun, it is not uncommon for a fastener to miss the stud during the installation process. This can damage an electrical conductor behind the wall. Electrical wiring for homes is typically 120 or 240 volts, and for commercial buildings, the voltages can be significantly higher. Thus, an installer is exposed to the risk of a severe electrical shock. A damaged wire may also create a dangerous fire hazard. Further, to decorate a completed building, pictures, clocks, lighting fixtures and other items are typically hung on walls using fasteners such as nails and screws. Since the electrical conductors behind these walls are hidden from view, the person hanging these items is exposed to the same hazards described above.
For these reasons, in 1990, the National Electrical Code (NEC) was amended to require that electrical conductors be secured at least one-and-one-quarter inches (1.25 in) behind the wall. Even in the absence of such regulation, it is, of course, prudent to secure electrical conductors a sufficient distance behind the wall to ensure that a nail or screw does not go through the wall into a conductor, thereby causing injury and/or creating a fire hazard.